@article{CMUC_1991__32_2_a12,
     author = {Weidemaier, Peter},
     title = {The trace theorem  $W^{2,1}_p(\Omega_T) \ni f \mapsto \nabla_{\!x} f \in W^{1-1/p,1/2-1/2p}_p(\partial \Omega_T)$ revisited},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {307--314},
     publisher = {mathdoc},
     volume = {32},
     number = {2},
     year = {1991},
     mrnumber = {1137792},
     zbl = {0770.46018},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1991__32_2_a12/}
}